Tokyo, November 12, 2015 --- Hitachi, Ltd. (TSE: 6501) and Tohoku University’s Advanced Institute for Material Research(AIMR) have developed a basic technology to reduce the internal resistance of the all-solid-state lithium ion battery (Li-ion battery) using a complex hydride*1 as a solid electrolyte. The reduction of internal resistance improves the charge-discharge performance of the all-solid-state Li-ion battery, resulting in the batteries (capacity: 2 mAh) successfully operating at temperatures as high as 150°C with a discharge capacity of 90% of theoretical value*2.